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Author Topic: Export DEM to Litchi  (Read 5429 times)

Xero

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Export DEM to Litchi
« on: December 30, 2018, 05:46:17 PM »
Hello every one. :)
For the people who know litchi (the drone way app) there is a possibility to import a DEM in the mission HUB but only to one format, which is : "WGS-84 Esri ASCII Grid".
What I would like to do it is to create such formated file with or from an DEM generated by Photoscan.
If any one know how to do so... big hugs and thanks  :D

ferengi

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Re: Export DEM to Litchi
« Reply #1 on: December 30, 2018, 06:48:58 PM »

Alexey Pasumansky

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Re: Export DEM to Litchi
« Reply #2 on: December 31, 2018, 01:50:40 PM »
Hello Xero,

Have you tried to select "Arc/Info ASCII Grid (*.acs)" file format when exporting DEM from PhotoScan?
Best regards,
Alexey Pasumansky,
Agisoft LLC

Xero

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Re: Export DEM to Litchi
« Reply #3 on: January 04, 2019, 08:01:38 PM »
Hello Xero,

Have you tried to select "Arc/Info ASCII Grid (*.acs)" file format when exporting DEM from PhotoScan?

I tried but still not good.

I contacted Litchi support and they answer me that :
"This DEM file isn’t in the correct format. xllcorner, yllcorner and cellsize must be in degrees (WGS-84 coordinate system)"

When I open the DEM file generated by Photoscan with excel
the xllcorner value is : 10.2004062543
the yllcorner value is : 59.7391018596

Any idea what are this values and how to convert them in degrees ?

Dave Martin

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Re: Export DEM to Litchi
« Reply #4 on: January 05, 2019, 12:36:01 AM »
So what WGS84 co-ordinates do you expect to see? i.e. what is the position of the Lower Left corner of your DEM?

Dave

Xero

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Re: Export DEM to Litchi
« Reply #5 on: January 07, 2019, 06:45:52 PM »
So what WGS84 co-ordinates do you expect to see? i.e. what is the position of the Lower Left corner of your DEM?

Dave

Thanks I've got some evolution with my problem.
I have now the datas in degres so until there it is ok.
Now Litchi support send me a file as a example with this information at the first lines when opened with text editor :
ncols         420
nrows         441
xllcorner     10.2004062543
yllcorner     59.7391018596
cellsize      0.00008978907956077
nodata_value  -9999.0


In the file generated with Photoscan I have this lines :
ncols        5769
nrows        5782
xllcorner    3.69843179636208
yllcorner    43.9510287132494
dx           2.460120000000039e-06
dy           1.777149999999827e-06
NODATA_value -32767.000


If I replace the dx           2.460120000000039e-06, dy           1.777149999999827e-06 lines by the value of the send file by cellsize      0.00008978907956077 I have a result when importing to Litchi but an erratic one.
So my question is how to get the cellsize line (with) correct value corresponding to my Photoscan generated DEM. BTW this value is in °.

marinevgeniev

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Re: Export DEM to Litchi
« Reply #6 on: July 24, 2022, 07:18:45 PM »
You have to export from Agisoft GeoTIFF.
Then import it to GlobalMapper.
From GlobalMapper you can export it in the format which Litchi want.

SvSz

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Re: Export DEM to Litchi
« Reply #7 on: October 09, 2022, 02:23:22 PM »
tried it out with global mapper trial with one project, smaller than 1 Acre, it did work. Now i have one that is less square-shaped, more longish and 10-20 Acres (still small, actually). I exported like 3 files from Global Mappers trial, but litchi turned grey after uploading it.

Sadly i cannot export more now with the trial of global mapper to try it out further. Is there a cheaper way, I'm not going to pay 600 dollars for this, haha...
i mean, i already have an expensive software with metashape professional, why is not able to do this??? ridiculous


My Workflow:

DEM (WGS 84 Pseudo-Mercator)
Export DEM (GeoTiff.tif)
Drag and Drop into Global Mapper
Right Click on Layer
Layer -> EXPORT -> Arc ASCII Grid -> Keep "OK"ying everything -> Save File as .asc
In LitchiHub: Import DEM -> Load the exported .asc (No Tick at Force Square Cells)
« Last Edit: October 09, 2022, 03:33:51 PM by SvSz »